What kind of swingarm is this?

[Tippmann98]

It's on a first gen 200x but I'm used to the square tube swingarm on them so what is this?

[Jason125m]

1983 atc 200x

[Dirtcrasher]

Dido, 83 is tubular...........

It's not a Westcoast!! :D

[Red Rider]

It's not a Westcoast!! :DBut it might be a Rustcoast. :D